The temporary structuring of hairstyles for an extended period of time lasting up to several days generally requires the use of setting agents. Hair treatment products that serve to temporarily shape the hair therefore play an important role. Such products for temporary shaping usually contain synthetic polymers and/or waxes as the setting agent. Products for supporting the temporary reshaping of keratin-containing fibers can be manufactured as hair spray, hair wax, hair gel, or styling mousse, for example.
The most important characteristic of a product for temporarily shaping hair, hereinafter also called styling product, is that the greatest possible hold is given to the treated fibers in their newly modeled shape—i.e., a shape that is impressed upon the hair. This is also referred to as a strong hairstyle hold or high holding strength of the styling product. The hairstyle hold is determined substantially by the type and quantity of the setting agents used, although the other components of the styling product can also have an impact.
Besides a high holding strength, styling products must meet a whole series of other requirements. These can be roughly subdivided into characteristics on the hair, characteristics of the respective formulation, e.g., characteristics of sprayed aerosols, and characteristics pertaining to the handling of the styling product, with particularly importance being placed on the characteristics on the hair. Particularly noteworthy are moisture resistance, low stickiness (tack), and a balanced conditioning effect. Moreover, a styling product should, to the greatest possible extent, be universally usable for all hair types and be gentle on hair and skin.
In order to meet the various requirements, a multitude of synthetic polymers have already been developed that are used as setting agents in styling products. These polymers can be subdivided into cationic, anionic, nonionic and amphoteric setting polymers.
European patents EP 1719499 B1, EP 1719500 B1 and EP 1726331 B1 describe acrylate resins with INCI designation acrylates/hydroxy ester acrylates copolymer and the use thereof in styling products. International patent application WO 2012/054278 A2 also mentions acrylates/hydroxy ester acrylates copolymers as hair-setting polymers and uses Acudyne® 1000 (The Dow Chemical Company) in styling mousses as an example.
Hair-setting products based on copolymers of styrene with (meth)acrylic acid and/or esters thereof are described in international patent application WO2012/168035 A1.
In principle, not every polymer and not every polymer blend is suitable for the manufacture of hair styling products. This is particularly true of hair sprays, in which the viscosity and therefore also the spraying behavior is influenced by the polymer and the quantity of polymer used, for example.
Even though suitable polymers and polymer combinations have been developed for use in the area of temporary hair-shaping for quite some time, the results that have been achieved thus far continue to leave room for improvement, particularly with regard to the storage stability, applicability and holding strength of these products. In particular, styling products that are currently available can still be improved in the sense that a good combination of holding strength and long-lasting hold (high-humidity curl retention) is not always sufficiently ensured.